1.9.2
Air Entrainment
Each class or mixture of concrete and mortar proposed for use in the work
shall have a total air content matching the total air content of the
adjacent concrete. Air content of the proposed mixture shall be determined
in accordance with ASTM C 231. When air-entrained concrete is required for
resistance to freezing and thawing, the concrete shall contain an
air-entraining admixture conforming to ASTM C 260 and having an air content
as indicated in ACI 301, (Table 3.4.1).
1.9.3
Admixtures
Concrete may contain admixtures, such as pigments, water reducers,
high-range water reducers, or set retarders to provide special properties
to the concrete. Use of admixtures shall be subject to approval.
1.9.4
Cementitious Content
Each class or mixture of concrete and mortar proposed for use in the work
shall have a cement content matching the cement content of the adjacent
existing concrete in order to provide uniform strength, weathering
characteristics, and appearance of repaired surfaces in relation to
existing surfaces.
1.9.5
Slump
Slump shall be determined in accordance with ASTM C 143/C 143M, and shall
be within the following limits:
Structural Element
Slump in mm*
Minimum
Maximum
Walls, columns, and beams
50
100
Foundation walls, substructure walls,
25
75
footings, pavement, and slabs
Any structural concrete approved
None
150
for placement by pumping
Structural Element
Slump in Inches*
Minimum
Maximum
Walls, columns, and beams
2
4
Foundation walls, substructure walls,
1
3
footings, pavement, and slabs
Any structural concrete approved
None
6
for placement by pumping
*These slump requirements do not apply when admixtures conforming to ASTM C
1017/C 1017M are approved to produce flowing concrete.
1.9.6
Technical Service for Specialized Concrete
The service of a technical representative shall be obtained to oversee
proportioning, batching, mixing, placing, consolidating, and finishing of
concrete and mortar, until field controls indicate specialized concrete of
SECTION 03900
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